The invention relates to a construction machine for the treatment of ground surfaces.
Construction machines of this type, e.g. large-sized milling devices or cold milling devices, comprise a machine frame having supported therein a milling drum extending transversely to the moving path to be treated. The machine frame further accommodates the milling-drum drive unit and is supported, in a manner allowing for height adjustment, by a plurality of track assemblies arranged before and behind the milling drum.
Such large-sized milling device and cold milling devices, or recyclers, are used for the milling of road surfaces, e.g. on highways or country roads. The milling drums have their outer surfaces equipped with exchangeable tools. In case of extremely hard road surfaces, it may happen that the tools have a service life as brief as only half an hour and that all of the tools of the milling drum have to be replaced thereafter. For this purpose, the chassis or the milling drum is arranged to be lifted until the milling drum is not in contact with the ground surface anymore. After swinging away a housing member of the roller housing, an operating person can perform the exchanging of the tools. In such construction machines with mechanical drive, the milling drum has to be rotated from time to time to allow the exchange of the tools. This rotation can be carried out by hand, which, however, requires considerable forces. It is also known to rotate the work or milling drum by means of a hand-operated crank, with the crank being coupled to a reduction gear of the milling drum. Since the crank can be arranged only on the outer side of the machine, the tool-exchanging process will ultimately require two operating persons.
Rotating the work or milling drum by use of the drive motor is excluded for safety reasons. Besides, the work roller is to be advanced only by a small rotational angle so that the next row of tools can be exchanged.